Squash Odysseus development history

static/js/editor/gradient-stops.js

@@ -0,0 +1,63 @@
+/** Shared normalization for editable linear-gradient stops. */
+
+export const MAX_GRADIENT_STOPS = 12;
+
+function finite(value, fallback, min, max) {
+  const parsed = Number(value);
+  return Number.isFinite(parsed) ? Math.max(min, Math.min(max, parsed)) : fallback;
+}
+
+function color(value, fallback) {
+  const text = String(value || '').trim();
+  return text || fallback;
+}
+
+export function legacyGradientStops({
+  start = '#ffffff',
+  mid = '#808080',
+  midEnabled = false,
+  midPosition = 50,
+  end = '#000000',
+} = {}) {
+  const stops = [{ position: 0, color: color(start, '#ffffff') }];
+  if (midEnabled) {
+    stops.push({
+      position: finite(midPosition, 50, 1, 99),
+      color: color(mid, '#808080'),
+    });
+  }
+  stops.push({ position: 100, color: color(end, '#000000') });
+  return stops;
+}
+
+export function normalizeGradientStops(value, legacy = {}) {
+  const source = Array.isArray(value) && value.length ? value : legacyGradientStops(legacy);
+  const stops = source.map((stop, index) => ({
+    position: finite(stop?.position, index === 0 ? 0 : 100, 0, 100),
+    color: color(stop?.color, index === 0 ? '#ffffff' : '#000000'),
+  }));
+  stops.sort((a, b) => a.position - b.position);
+
+  const unique = [];
+  for (const stop of stops) {
+    const previous = unique.at(-1);
+    if (previous && Math.abs(previous.position - stop.position) < 0.0001) {
+      unique[unique.length - 1] = stop;
+    } else {
+      unique.push(stop);
+    }
+  }
+  if (!unique.length || unique[0].position > 0) {
+    unique.unshift({ position: 0, color: unique[0]?.color || '#ffffff' });
+  } else {
+    unique[0].position = 0;
+  }
+  if (unique.at(-1).position < 100) {
+    unique.push({ position: 100, color: unique.at(-1)?.color || '#000000' });
+  } else {
+    unique.at(-1).position = 100;
+  }
+  const first = unique[0];
+  const last = unique.at(-1);
+  return [first, ...unique.slice(1, -1).slice(0, MAX_GRADIENT_STOPS - 2), last];
+}